1. Field of the Invention
The present invention relates to a computer system, and more specifically to a computer system equipped with a back-up power supply system for holding the contents of a memory device.
2. Description of Background Information
In computer systems, the initialization, i.e., a process of setting counters, switches and addresses to zero or other starting values, is required at each time of "power-on" of the system. However, in the case of the computer systems having a back-up power supply, it is not desirable if the initialization of the memory takes place after recovering from a "power down mode" in which the power current is supplied from the back-up power supply. Conventionally, to avoid such a condition, a particular circuit is provided for discriminating types of reset operation, that is, a power-on reset after the normal throw-in of the power current and a reset operation after recovering from the "power down mode", so that the initialization of the computer system is effected only in the case of the normal reset operation after the throw-in of the power current. However, the drawback was that the provision of such a discrimination circuit has resulted in an increase in cost and it is desirable to realize the function of such circuit without using any additional circuit.